1. Field of the Invention
The present invention relates to the technical field of touch display devices and, more particularly, to a high-sensitivity in-cell touch display device.
2. Description of Related Art
A typical touch display device is provided by mounting a touch panel on a display panel with a complicated process and high material cost, which relatively reduces the light penetration rate and thus degrades the display quality. In addition, the additional volume and weight of the touch panel are disadvantageous to the trend of compactness and energy conservation and emission reductions for electronic devices. Accordingly, the in-cell touch display panels are getting more and more important in various industries.
In a typical in-cell touch display panel, in order to overcome the problem of having huge capacitance between a common electrode and the sensing electrodes, the common electrode is divided into a plurality of electrodes that are also operated as the touch electrodes. Furthermore, in order to overcome the severe SNR deterioration caused by a display signal coming from the TFT layer connection, a time sharing is applied for a touch sensing in a short display silent interval (vertical or horizontal synchronous interval) of a non-display operation, which can be seen in US patent publications US2014062907 entitled “Display device with an integrated touch screen and method of driving the same”, US2012086665 entitled “Liquid crystal display device”, and US2013314342 entitled “Touch sensing device and method for driving the same”, for example. In the aforementioned typical in-cell touch display panels, when the resolution of the screen is increased, the display operation is difficult to have enough time for a touch sensing operation. Likewise, when the size of the screen is enlarged, the number of touch points is relatively increased and thus more time is required to scan the touch sensing electrodes. Accordingly, time division becomes difficult, resulting in that the resolution of the in-cell touch screen is limited and the size of the screen is restricted.
Therefore, it is desirable to provide an improved in-cell touch display device to mitigate and/or obviate the aforementioned problems.